This invention relates to the guarding of machines such as "presses". One type of press which is intended to act on and thus to close binding elements for packets of paper, is a jaw which is moveable relative to a second jaw or surface to close a binding element through perforations in a packet of paper to bind the sheets of paper together. A machine of this type is described in British Patent No. 2083408.
With such a press the stroke of the moveable jaw has to be variable so as to accommodate different thicknesses of packets of paper and different thicknesses of binding elements.
As the packets of paper are fed manually between the jaw and co-operating surface/jaw, a guard needs to be provided to prevent a user's fingers from being trapped between the jaw and co-operating surface.
Hitherto a guard plate has been provided which is intended partially to cover the opening between the jaw and co-operating jaw or surface and which may be manually adjustable when the stroke of the moveable jaw is adjusted.
If for example a relatively large opening between the jaw/co-operating surface is to be provided to admit a relatively thick packet to be bound then the position of the moveable jaw is adjusted upwardly and the guard is positioned in an upper position. When in this position a user's fingers may be able to enter the space between jaw/co-operating surface but would not be crushed because the end of the stroke of the moveable jaw is well above the base plate.
If however the guard is left in this position and the position of the moveable jaw is lowered so as to be able to act on the binding elements of a thinner packet of sheets, then there is a danger that a user's fingers could indeed be trapped when the machine is operated pneumatically by for example the operation of a foot pedal or the like.